Norwich to Tilbury – Priority Trenching

Headland Archaeology is delivering a programme of archaeological trial trenching for National Grid to support a proposed 184km electricity transmission connection between substations at Norwich and Tilbury, with discoveries to date ranging from prehistoric features to Second World War airfields.

The initial phase of ‘priority trenching’ works comprised approximately 3,350 trial trenches across 55 working areas, alongside geophysical surveys and archaeological and geoarchaeological monitoring of Ground Investigation works at key locations along the scheme. The trenching targeted underground cabling sections of the scheme, substations and other programme-critical elements. This initial phase of works commenced in September 2024, and was due for completion in March 2026, with the majority completed by the end of 2025. The results will inform the Development Consent Order (DCO) submission and support the scheme’s Heritage proposals.

Spanning 184 km across Norfolk, Suffolk, and Essex, the scheme provides an unparalleled archaeological cross-section through the East Anglian landscape and its past. Archaeological sites identified to date include WWI and WWII airfields, agricultural and rural medieval settlements, a Romano-British farmstead (among numerous other Roman period sites), and a wide range of prehistoric features. Key finds include Bronze Age arrowheads, coins from the Roman period onwards, high status Roman pottery, a Roman road, a lion-headed casket mount found within a burial context, medieval pottery production waste, and evidence relating to potential witchcraft.

Delivery of works across the length of the scheme has required extensive collaboration, including agreeing a joint archaeological scope between multiple local authorities, coordinating access with hundreds of landowners, and working closely with a broad client team and subcontractors, including land liaison specialists, ecologists, and Unexploded Ordnance (UXO) engineers. The project has also required a high level of planning and adaptability, particularly in relation to land access, logistics, and managing a dynamic programme across a linear route with multiple concurrent work fronts.

A further stage of non-priority trenching is planned to follow this phase, of similar scope but increased logistical complexity. This will enable a detailed evaluation of the route and identify requirements for further archaeological investigation. This will inform future mitigation proposals and extend the trenching programme into its third year, underscoring both the scale of the project and Headland’s commitment to maintaining high standards through robust procedural and management systems.